The authors examined inductive reasoning among experts in a domain. Three t
ypes of tree experts (landscapers, taxonomists, and parks maintenance perso
nnel) completed 3 reasoning tasks. In Experiment 1, participants inferred w
hich of 2 novel diseases would affect "more other kinds of trees" and provi
ded justifications for their choices. In Experiment 2, the authors used mod
ified instructions and asked which disease would be more likely to affect "
all trees." In Experiment 3, the conclusion category was eliminated altoget
her, and participants were asked to generate a fist of other affected trees
. Among these populations, typicality and diversity effects were weak to no
nexistent. Instead, experts' reasoning was influenced by "local" coverage (
extension of the property to members of the same folk family) and causal-ec
ological factors. The authors concluded that domain knowledge leads to the
use of a variety of reasoning strategies not captured by current models of
category-based induction.